An optimal operating point of such a hybrid drive is for example determined and adjusted in relation to the emission behavior or the fuel consumption of the drive. The publication document DE 10 2010 008 695 A1 describes a method, with which at any point of time an optimal operating point for a hybrid drive system can be determined and provided dependent on the torque demanded by the driver. The exhaust gas temperatures of combustion engines, especially diesel engines, are reduced because of such optimizations which generally increase the efficiency degree. Especially in hybrid drives, consumption reducing measures lead to a reduction of the exhaust gas temperature. An essential disadvantage of lower exhaust gas temperatures because of more efficient combustion engines is the slower cold starting heat-up of the exhaust gas post-treatment device. Furthermore, disadvantageously a lower passive filter regeneration is connected therewith, so that the filter regeneration intervals are shortened, wherein the heating-up of the filter for the soot burn-off in the regeneration operation is again connected with an increased fuel consumption.